From late 1896 through early 1897, a full ten years before the flight of the first known powered dirigible, thousands of people across America claimed to see strange lights in the night sky; heard voices and music emanating from a mysterious airship. Some accounts described a cigar-shaped gasbag, others noted vast, flapping canvas wings and large wheels like a paddle steamer's. One early eye witness even insisted he'd glimpsed two men suspended in the ship's undercarriage, furiously working bicycle pedals. From Sacramento to Chicago, folks from all walks of life strove to convince skeptical journalists that what they'd seen was not, in fact, an elaborate hoax.
The most carefully researched book written to date about the phenomenon is probably The Great Airship Mystery by Daniel Cohen. Cohen gives a well-rounded account of the circumstances and evidence before concluding --quite sensibly-- that the airship probably never existed. (Bummer.)
Several other authors have offered up far more juicy theories. Michael Busby maintains in his own book Solving the 1879 Airship Mystery that a secret society of mad genius inventors joined forces to build a handful of highly advanced aircraft worthy of Jules Verne, each of which, after being viewed by countless drunken farmhands in the Midwest, inexplicably crashed and burned over the Atlantic ocean.
Noted ufologist/parapsychologist/journalist John Keel includes the sightings in the book UFOs: Operation Trojan Horse as compelling evidence for his long-standing hypothesis that certain "non-human or spiritual intelligence sources" have been staging elaborate events for centuries to manipulate and misinform the human pysche. (Other examples he cites as include the fairy folk of Middle Europe, vampire legends, black helicopter sightings, poltergeist phenomena and UFOs.)
Although the initial sightings in the US ended in 1897, several more sightings occurred in England, Europe and New Zealand from 1909 through 1913. In 1912, vaudeville superstars Elsie Baker and Billy Murray recorded a little ditty about the airship fervor entitled "Mysterious Moon" and recorded it on wax cylinder.